The present invention generally relates to a water treatment system and more particularly, to an inductively coupled ballast for non-contact power transfer to an ultraviolet lamp in the water treatment system.
The present invention addresses several problems associated with previous point-of-use home or office water treatment systems. A first problem is that conventional water treatment systems, utilizing lamp assemblies with ultraviolet lamps therein, are energy-inefficient. The lamp assemblies are generally left continuously running to prevent microorganisms from reproducing within the water treatment system as a result of the ultraviolet lamp not being turned on. When a conventional lamp assembly is turned on, it takes a significant amount of start-up time before gas within the ultraviolet lamp is sufficiently excited to output light of a predetermined intensity level required to insure adequate destruction of microorganisms within the water treatment system. Water which is discharged from the water treatment system before an ultraviolet lamp is sufficiently excited may carry an unacceptably high level of live microorganisms. A continuously running lamp assembly uses a significant amount of energy and is, therefore, inefficient. Also, with the lamp assembly left running continuously, such as overnight, water residing within a water treatment system unit can become uncomfortably warm.
A second problem is with the design of reflector assemblies within water treatment systems. In an attempt to increase lamp efficiency, reflector assemblies may be placed about ultraviolet lamps and water-carrying conduits in which the microorganisms are irradiated. Light incident from the ultraviolet lamps which misses striking the water-carrying conduits is reflected back from the reflector walls and have a chance to again impinge upon the water-carrying conduits. Often these reflector assemblies are circular in cross-section. Unfortunately, a lot of the ultraviolet light produced never reaches the water-carrying conduits. Rather, a significant portion of light is reabsorbed by the ultraviolet lamp assembly.
A third problem involves the electrical coupling of the lamp assemblies to the water treatment systems. Every time a lamp assembly is installed in or removed from a water treatment system, the lamp assembly must be mechanically and electrically coupled and uncoupled relative to the water treatment system. This often requires complicated and expensive mounting assemblies. Further, care must be taken to insure that the electrical connections are not exposed to moisture while electrical power is passing through the water treatment system.
Coaxially aligned lamp assemblies and filter assemblies are sometimes used to minimize the size of water treatment systems. A lamp assembly and filter assembly in a particular water treatment system may or may not be simultaneously removed from the water treatment system. If these assemblies are simultaneously removed, they are often very heavy as they may be filled with water and have substantial weight on their own. Alternatively, even if the lamp assembly and filter assembly are separably removable from a water treatment system, quite often problems of water spilling from one of these assemblies during handling.
Another problem faced by water treatment system units having lamp assemblies is that complicated monitoring systems are needed to monitor the lamp assemblies. As a lamp assembly ages, the intensity of light output from the lamp assembly generally diminishes. Eventually, the intensity falls below a level necessary to effect a desired microorganism-kill rate. The lamp assembly should be removed before the critical minimum intensity is reached. Accordingly, a monitor system is required to check on the light intensity within the water treatment system. These monitoring systems are typically expensive. They often require costly ultraviolet sensors with quartz windows.
Conventional ballast control circuits employ bipolar transistors and saturating transformers to drive the lamps. The ballast control circuits oscillate at frequencies related to the magnetic properties of the materials and winding arrangements of these transformers. Circuits with saturating transformer oscillators produce an output in the category of a square wave, require the transistors of the half bridge to hard-switch under load and require a separate inductor to limit the current through the discharge lamp.
These and other deficiencies in prior water treatment system units employing lamp assemblies and filter assemblies are addressed by the present invention.
The present invention discloses an electronic control system for a water treatment system that includes an inductively coupled ballast circuit. The water treatment system filters water by, amongst other things, directing a flow of water from a water supply to a filter assembly. The filter assembly removes unwanted particulates from the flow of water. After passing through the filter assembly, the water is directed to a replaceable ultraviolet lamp assembly. The ultraviolet lamp assembly destroys organic matter in the supply of water by exposing the water to high-intensity ultraviolet light as the water flows through the ultraviolet lamp assembly. The ultraviolet lamp assembly provides virtually instantaneous high-intensity ultraviolet light at the beginning of operation, which provides advantages over prior art water treatment systems that require warm-up time. After exiting the ultraviolet lamp assembly, the flow of water is directed out of the water treatment system through an outlet assembly.
The overall operation of the water treatment system is controlled by a control unit that is electrically connected with the ultraviolet lamp assembly and the filter assembly. In the preferred embodiment, the control unit is also electrically connected with a flow sensor, an ambient temperature sensor circuit, an ambient light sensor circuit, an ultraviolet light sensor circuit, a power detection circuit, a display, an audio generation circuit, a memory storage device, a communications port and a radio frequency identification system. These devices are all monitored or controlled by the control unit and provide various benefits to the water treatment system, as will be generally set forth below.
The flow sensor circuit is used by the control unit to determine when water is flowing, so that the ultraviolet lamp assembly can be energized, and to keep track of the volume of water that is being processed by the water treatment system. The ambient temperature sensor circuit measures the ambient temperature of the atmosphere, so that the water treatment system can maintain a temperature level above freezing or some other predetermined temperature. The ultraviolet light sensor circuit provides the control unit with electrical signals corresponding to the intensity of the ultraviolet light that is being emitted by the ultraviolet lamp assembly. This is important because these measurements allow the control unit to make adjustments that can increase or decrease the intensity of the ultraviolet light being emitted.
The power detection circuit provides the control unit with electrical signals that indicate the presence or absence of power to the water treatment system that is provided from a conventional external power source, such as a wall outlet. The display is controlled by the control unit and displays information on the status of the water treatment system. The audio generation circuit is used by the control unit to provide audible sounds in case predetermined system states occur in the water treatment system that require attention.
The water treatment system further includes a memory storage device that is electrically connected with the control unit. The memory storage device is used to store various data values related to the water treatment system and its related components. In the preferred embodiment of the present invention, the memory storage device is an EEPROM or some other equivalent storage device. A communications port is connected with the control unit, which provides the ability for bi-directional communication between the control unit and a peripheral device, such as a personal computer or hand-held monitoring device.
The radio frequency identification system includes an ultraviolet light transponder that is located in each ultraviolet lamp assembly. In addition, the radio frequency identification system includes a filter transponder that is located in the filter assembly. The ultraviolet light transponder and the filter transponder communicate, using radio frequency, with the radio frequency identification system. Each transponder contains certain information that is specific to the ultraviolet lamp assembly and the filter assembly. Those skilled in the art would recognize that contact-type identification systems may be used instead of the radio frequency identification system.
The preferred ultraviolet lamp assembly is energized by an inductively coupled ballast circuit. The preferred inductively coupled ballast circuit is a self-oscillating half-bridge switching design that operates at high frequencies that provide virtually instantaneous ultraviolet lamp illumination. In addition, the inductively coupled ballast circuit self-oscillates once resonance is achieved, uses MOSFET transistors as switching elements, and is designed to accommodate an air-core transformer coupling arrangement, which simplifies the design of an ultraviolet lamp assembly. The ultraviolet lamp assembly may be readily replaced, because of the air-core transformer coupling arrangement created by the inductively coupled ballast circuit.
The preferred inductively coupled ballast circuit includes a control circuit, an oscillator, a driver, a half-bridge switching circuit, a series resonant tank circuit, a secondary coil, a resonant lamp circuit and a ultraviolet lamp. The oscillator is electrically connected with the control unit, which starts the oscillator by providing electric signals to the control circuit that energizes the oscillator. During operation, the oscillator provides electrical signals to the driver, which then causes the half-bridge switching circuit to become energized. The half-bridge switching circuit energizes the series resonant tank circuit that, in turn, inductively energizes the ultraviolet lamp in the ultraviolet lamp assembly.
The ultraviolet lamp assembly physically houses the secondary coil, the resonant lamp circuit and the ultraviolet lamp of the inductively coupled ballast circuit. Once the series resonant tank is energized, the secondary coil in the ultraviolet lamp assembly becomes inductively energized, thereby illuminating the ultraviolet lamp. In the preferred embodiment, the resonant frequency for the inductively coupled ballast circuit is about 100 kHz. As such, the secondary coil in the ultraviolet lamp assembly resonates at about 100 kHz as well. As previously set forth, the resonant frequency of operation can be adjusted up or down by the control unit to accommodate for convenient component selection. In addition, the resonant frequency is also controlled by the component selection in the series resonant tank, which will be set forth in detail below.
As such, a preferred embodiment of the present invention discloses a fluid treatment system that comprises a control unit; an inductively coupled ballast circuit that is inductively coupled with an electromagnetic radiation emitting assembly, wherein the inductively coupled ballast circuit inductively energizes an electromagnetic radiation emitting device in the electromagnetic radiation emitting assembly in response to a predetermined electric signal from the control unit.
Another preferred embodiment of the present invention discloses a method of providing electromagnetic radiation in a fluid treatment system. The method comprises the steps of generating a predetermined electric signal with a control unit; directing the predetermined electric signal to an inductively coupled ballast circuit; and inductively energizing an electromagnetic radiation emitting device in the inductively coupled ballast circuit in response to the predetermined electric signal from the control unit.
In another preferred embodiment of the present, a fluid treatment system with a radio frequency identification system is disclosed. The fluid treatment system comprises a control unit; a base station electrically connected to the control unit; and at least one radio frequency identification transponder located in a electromagnetic radiation emitting device assembly that is in radio communication with the base station. In yet another preferred embodiment of the present invention, the electromagnetic radiation emitting assembly is replaced with a filter assembly.
Another preferred method disclosed by the present invention relates to a method of monitoring electromagnetic radiation emitting assembly information in a fluid treatment system. The method comprises the steps of providing an electromagnetic radiation emitting assembly for use in the fluid treatment system; generating an electromagnetic radiation emitting assembly information signal with an electromagnetic radiation emitting identification transponder located in the electromagnetic radiation emitting assembly; transmitting the electromagnetic radiation emitting assembly information signal to a base station located in the fluid treatment system; and directing said electromagnetic radiation emitting assembly information signal to a control unit. In another preferred embodiment, the electromagnetic radiation emitting assembly can be replaced with a filter assembly.
These and other features and advantages of the invention will become apparent upon consideration of the following detailed description of the presently preferred embodiments of the invention, viewed in conjunction with the appended drawings.